Inson



(No Model.)

- T. G. ROBINSON.

RIMMING ATTACHMENT FOR SEWING MACHINES. .No. 255,336. Patented am. 21,1882.

' UNITED STATES PATENT" OFFICE.

THOMAS c. noBINsoN, on CAMBRIDGE, MASSACHUSETTS, AssieNoR TO HIMSELF AND E. BAKER WELOH, or SAME PLACE.

TRIMMING ATTACHMENT FOR SEWING-MACHINES.

SPECIFICATION forming part of Letters Patent No. 255,336, dated March 21,1882.

Application filed November 11, 1881.

To all whom it may concern:

Be it known that i, THOMAS GROCKER Ron- INSON, a citizen of the United States, and aresident ofOambridge, Middlesex county, State ofMassachusetts, have invented certain Improvements in TrimmingAttachments for Sewing-Machines,of which the following isaspecification. My invention relates to that class of sewing-machines in which a knife is arranged to operate in conjunction with sewing mechanism to trim off the material at a uniform distance from the'line of stitching; and my invention consists in constructing the knife, needle, and operating parts as fully described hereinafter, so as to insure more perfect results than can be attained by the parts constructed as heretofore.

In the drawings, Figure 1 is a perspective view of sufficient of a sewing-machine to illustrate my improvement. Fig. 2 is a side view of Fig. 1. Fig. 3 is a view of the knife. Fig. 4 is a plan showing the edge of a. shoe-upper partly sewed and trimmed; Fig. 5, a perspective view of the knife, needle, and upper Fig. 6, a side view, showing a different mode of pivoting the lever; and Fig. 7, a detached view, showing the link-connection of the lever.

The sewing-machine may be constructed in any suitable manner. In the drawings I have represented an ordinary construction, comprising parts of the bed-plate A, overhanging arm B, needle bar lever or arm 0, and the head D, needle-bar E, presser-bar F, carrying .a roller presser-foot, G, and tension and take-up appliances.

. In the head D are openings to receive a supplemental bar, H, to the lower end of which is detachably connected the knife I, the bar extending through a block, a, pivoted to alever, J, hung to an arm, I), projecting from the head D, and connected at the inner end by a link, 0, to the needle-bar arm. The bar H is adj ustably secured in the block a by a set-screw, d. The knife is bent so as to extend laterally from the knife-bar H to a position adjacent and parallel to the needle, and thelower cutting-edge, or, parallel to the cutter-plate 7t, occupies a po- (No model.)

sition at the rear of the needle parallel to the line in which the feed-claw 0 moves.

From the edge of the knife, at the side opposite that approached by the work as it is fed forward, extends downward a finger, i, which enters an opening in the cutter-plate and serves as a guard, preventing the work from slipping beneath the knife, and the back edge, a, of the knife is prolonged upward as a straight continuation of the edge of the guard until it meets the shoulder m, formed by the lateral extension or bend of the knife.

The character of the work is illustrated in Fig. 4, representing the scalloped edge of a shoe-upper, which is sewed by the needle along the line it, while at the same time the knifeI, raised and lowered rapidly by the action of the needle-bar arm through the lever J and link 0, shears or trims off the work to a uniform distance from the line of stitching.

It will be seen thatthe different scallops meet, forming sharp or -shaped corners u,- and it has been found in practice that with ordinary appliances it is difticnlt to trim out these narrow spaces, owing to the fact that the work mustbe kept flat upon the plate in using such appliances.

By prolonging the edge u of the knife above the cutting-edge, and arranging the shoulder at high above the work-plate, 1 am enabled to turn up the finished scallop to, Fig. 5, so that the knife can occupy a position at the extremity of the notch as the work is turned, thereby permitting the cutting operation on the next scallop to begin at the extreme end.

Heretofore the construction has been such that the scallop could not be turned up nor the knife carried back into the notch, and consea collar, f, secured adjustably by a set-screw, d, and carrying a rod, g, which enters a hole in the needle-head and guides the bar vertically, while preventing it from turning during its operation.

By loosening the set-screws d d the knifebar may be turned toany desired position and then secured.

Other devices may be employed to guide and permit the adjustment of the knife-bar, and also for reciprocating the same.

The cutter-plate I, against which the knife shears, is slotted to receive thesecuring-screws, or is otherwise adjustable, so that it may be brought to position to shear with the knife with the utmost accuracy.

As the knife must be hroughtclose and parallel to the needle, as well as extended upward to form thelong edge a above the cutting-edge, it is not possible to employ a needle-bar extending for the usual extent below the head, as it would strike the knife. I therefore cut off the needle-bar and provide the needle with a long shank, g, which supports the needle beyond the end of the bar at the side of the knife.

In many machines it would not be practicable to use the lever arrangement shown in Figs. 1 and 2 and heretofore employed by me, for which purpose I in such cases place the fulcrum of the lever J between the rear end of the latter and the knife-bar, as shown in Fig. 6. In this case I use a link, 0, and double fulcrum \V, as shown in Figs. 6 and 7, and the pivoted block a is at the end of the lever, to which motion is communicated from the needle-bar by a lever, Z.

I claim 1. A trimming knife for sewing-machines, consisting of a flat blade having a horizontal cutting-edge, .23, a finger, i, projecting downward at one edge thereof, and with a lateral shoulder arranged at the side opposite the cutting-edge and above the latter at a height sufiicient to permitthe work tobe turnedu eiagainst the rear edge of the knife, substantially as set forth.

2. The trim ming-knife consisting of a blade sharpened to form a horizontal cutting-edge, a2, provided with a finger, t, and an edge, u, constituting a prolongation of the side of the finger, and extended laterally from said edge u to form a shoulder, m, arranged substatitially as set forth.

3. The combination, in a sewing-machine, with the needle and resser-bars, of a cutterhar, H, appliances for reciprocating the same, and a knife having a horizontal cutting-edge and a finger, i, at the side opposite that toward which the fabric is fed, and connected to the cutter bar and extending laterally to a position parallel and behind and adjacent to the needle, substantially as set forth.

4. The combination of the bar H, lever J, pivoted block a, and set-screw securing the bar adjustahly in said block, substantially as set forth.

5. The combination, with the base-plate ofa sewing-machine, and with a reciprocating flat knife arranged in close proximity to the needle and having a horizontal cutting-edge, or, and a finger, i, at the side of said knife opposite that toward which the fabric is fed, of an adjustable cutter-plate, is, substantially as set forth.

6. The combination, in a sewing-machine, of the-needle-bar, cutter-bar H, levers Z and J, link W, pivoted to the lever J and to the arm B, and link 0, as set forth.

In testimony whereofI have signed my name to this specification in the presence of two subscribing witnesses.

THOMAS OROGKER ROBINSON.

Witnesses:

O. F. BROWN, E. B. WELoH. 

